Wash the raspberries. Heat the fruits together with the coconut blossom sugar in a saucepan and stir until the coconut blossom sugar has dissolved. Strain the mixture through a sieve and let it cool to room temperature.
In the meantime, dice the watermelon and wash the lemons with hot water and cut them in half. Squeeze one lemon, cut the other into thin slices.
Puree the raspberry pulp, lemon juice and watermelon in a blender and chill until serving. Fill a glass 3/4 full with the drink and ice cubes and fill the remaining quarter with mineral water.
Garnish the drink with the lemon wedges and fresh mint.